Liquid crystal displays can have various advantages such as lightness, thinness, low cost, low power consumption for operation, and improved adherence to an integrated circuit. Liquid crystal displays have been widely used in laptop computers, monitors, and TV screens.
Liquid crystal displays include a color filter formed by repeating a unit pixel, in which three primary color sub-pixels of red (R), green (G), and blue (B) are combined. The unit pixel displays a particular color due to the combination of three primary colors when each sub-pixel is adjacently disposed and then, applied by a color signal and controlled about brightness.
The color filter is made of red (R), green (G), and blue (B) color dyes or pigments. These color materials change white light from a backlight unit into each corresponding color light.
Because the color materials have a spectrum with no unnecessary wavelength other than a required absorption wavelength and a smaller absorption band, display performance of the color filter may be improved. In addition, the color materials are required to have excellent heat resistance, light resistance, and chemical resistance without being faded or discolored when exposed to ultraviolet (UV), acid, and/or base during etching of a color resist.
The color filter can be fabricated using a photosensitive resin composition by dyeing, electrophoretic deposition (EPD), printing, pigment dispersion, and the like, in which three or more colors are coated on a transparent substrate. There have been recent improvements to the pigment dispersion method to provide improved color reproducibility and durability for heat, light, and humidity and thus, pigment dispersion methods have been widely adopted.
However, when a pigment-type photosensitive resin composition is used to fabricate a color filter, the color filter has a limit of deteriorated luminance and contrast ratio due to size and cohesion of pigment particles. In order to improve these limits, research has been conducted on a photosensitive resin composition including a dye that does not form a particle or has a very smaller primary particle diameter. However, the dye-type photosensitive resin composition can have poor heat resistance, light resistance, and chemical resistance and has limited commercial availability. Accordingly, there is a need to improve the reliability of dye-type photosensitive resin compositions for commercial availability.